NetBSD-5.0.2/sys/kern/kern_cctr.c
/* $NetBSD: kern_cctr.c,v 1.8 2008/05/19 17:06:02 ad Exp $ */
/*-
* Copyright (c) 2006, 2008 The NetBSD Foundation, Inc.
* All rights reserved.
*
* re-implementation of TSC for MP systems merging cc_microtime and
* TSC for timecounters by Frank Kardel
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/* basic calibration ideas are (kern_microtime.c): */
/******************************************************************************
* *
* Copyright (c) David L. Mills 1993, 1994 *
* *
* Permission to use, copy, modify, and distribute this software and its *
* documentation for any purpose and without fee is hereby granted, provided *
* that the above copyright notice appears in all copies and that both the *
* copyright notice and this permission notice appear in supporting *
* documentation, and that the name University of Delaware not be used in *
* advertising or publicity pertaining to distribution of the software *
* without specific, written prior permission. The University of Delaware *
* makes no representations about the suitability this software for any *
* purpose. It is provided "as is" without express or implied warranty. *
* *
******************************************************************************/
/* reminiscents from older version of this file are: */
/*-
* Copyright (c) 1998-2003 Poul-Henning Kamp
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
/* __FBSDID("$FreeBSD: src/sys/i386/i386/tsc.c,v 1.204 2003/10/21 18:28:34 silby Exp $"); */
__KERNEL_RCSID(0, "$NetBSD: kern_cctr.c,v 1.8 2008/05/19 17:06:02 ad Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/time.h>
#include <sys/timetc.h>
#include <sys/kernel.h>
#include <sys/power.h>
#include <sys/cpu.h>
#include <machine/cpu_counter.h>
/* XXX make cc_timecounter.tc_frequency settable by sysctl() */
static timecounter_pps_t cc_calibrate;
void cc_calibrate_cpu(struct cpu_info *);
static int64_t cc_cal_val; /* last calibrate time stamp */
static struct timecounter cc_timecounter = {
.tc_get_timecount = cc_get_timecount,
.tc_poll_pps = cc_calibrate,
.tc_counter_mask = ~0u,
.tc_frequency = 0,
.tc_name = "unkown cycle counter",
/*
* don't pick cycle counter automatically
* if frequency changes might affect cycle counter
*/
.tc_quality = -100000,
.tc_priv = NULL,
.tc_next = NULL
};
/*
* initialize cycle counter based timecounter
*/
struct timecounter *
cc_init(timecounter_get_t getcc, uint64_t freq, const char *name, int quality)
{
if (getcc != NULL)
cc_timecounter.tc_get_timecount = getcc;
cc_timecounter.tc_frequency = freq;
cc_timecounter.tc_name = name;
cc_timecounter.tc_quality = quality;
tc_init(&cc_timecounter);
return &cc_timecounter;
}
/*
* pick up tick count scaled to reference tick count
*/
u_int
cc_get_timecount(struct timecounter *tc)
{
struct cpu_info *ci;
int64_t rcc, cc, ncsw;
u_int gen;
retry:
ncsw = curlwp->l_ncsw;
__insn_barrier();
ci = curcpu();
if (ci->ci_cc.cc_denom == 0) {
/*
* This is our first time here on this CPU. Just
* start with reasonable initial values.
*/
ci->ci_cc.cc_cc = cpu_counter32();
ci->ci_cc.cc_val = 0;
if (ci->ci_cc.cc_gen == 0)
ci->ci_cc.cc_gen++;
ci->ci_cc.cc_denom = cpu_frequency(ci);
if (ci->ci_cc.cc_denom == 0)
ci->ci_cc.cc_denom = cc_timecounter.tc_frequency;
ci->ci_cc.cc_delta = ci->ci_cc.cc_denom;
}
/*
* read counter and re-read when the re-calibration
* strikes inbetween
*/
do {
/* pick up current generation number */
gen = ci->ci_cc.cc_gen;
/* determine local delta ticks */
cc = cpu_counter32() - ci->ci_cc.cc_cc;
if (cc < 0)
cc += 0x100000000LL;
/* scale to primary */
rcc = (cc * ci->ci_cc.cc_delta) / ci->ci_cc.cc_denom
+ ci->ci_cc.cc_val;
} while (gen == 0 || gen != ci->ci_cc.cc_gen);
__insn_barrier();
if (ncsw != curlwp->l_ncsw) {
/* Was preempted */
goto retry;
}
return rcc;
}
/*
* called once per clock tick via the pps callback
* for the calibration of the TSC counters.
* it is called only for the PRIMARY cpu. all
* other cpus are called via a broadcast IPI
* calibration interval is 1 second - we call
* the calibration code only every hz calls
*/
static void
cc_calibrate(struct timecounter *tc)
{
static int calls;
struct cpu_info *ci;
KASSERT(kpreempt_disabled());
/*
* XXX: for high interrupt frequency
* support: ++calls < hz / tc_tick
*/
if (++calls < hz)
return;
calls = 0;
ci = curcpu();
/* pick up reference ticks */
cc_cal_val = cpu_counter32();
#if defined(MULTIPROCESSOR)
cc_calibrate_mp(ci);
#endif
cc_calibrate_cpu(ci);
}
/*
* This routine is called about once per second directly by the master
* processor and via an interprocessor interrupt for other processors.
* It determines the CC frequency of each processor relative to the
* master clock and the time this determination is made. These values
* are used by cc_get_timecount() to interpolate the ticks between
* timer interrupts. Note that we assume the kernel variables have
* been zeroed early in life.
*/
void
cc_calibrate_cpu(struct cpu_info *ci)
{
u_int gen;
int64_t val;
int64_t delta, denom;
int s;
#ifdef TIMECOUNTER_DEBUG
int64_t factor, old_factor;
#endif
val = cc_cal_val;
s = splhigh();
/* create next generation number */
gen = ci->ci_cc.cc_gen;
gen++;
if (gen == 0)
gen++;
/* update in progress */
ci->ci_cc.cc_gen = 0;
denom = ci->ci_cc.cc_cc;
ci->ci_cc.cc_cc = cpu_counter32();
if (ci->ci_cc.cc_denom == 0) {
/*
* This is our first time here on this CPU. Just
* start with reasonable initial values.
*/
ci->ci_cc.cc_val = val;
ci->ci_cc.cc_denom = cpu_frequency(ci);
if (ci->ci_cc.cc_denom == 0)
ci->ci_cc.cc_denom = cc_timecounter.tc_frequency;;
ci->ci_cc.cc_delta = ci->ci_cc.cc_denom;
ci->ci_cc.cc_gen = gen;
splx(s);
return;
}
#ifdef TIMECOUNTER_DEBUG
old_factor = (ci->ci_cc.cc_delta * 1000 ) / ci->ci_cc.cc_denom;
#endif
/* local ticks per period */
denom = ci->ci_cc.cc_cc - denom;
if (denom < 0)
denom += 0x100000000LL;
ci->ci_cc.cc_denom = denom;
/* reference ticks per period */
delta = val - ci->ci_cc.cc_val;
if (delta < 0)
delta += 0x100000000LL;
ci->ci_cc.cc_val = val;
ci->ci_cc.cc_delta = delta;
/* publish new generation number */
ci->ci_cc.cc_gen = gen;
splx(s);
#ifdef TIMECOUNTER_DEBUG
factor = (delta * 1000) / denom - old_factor;
if (factor < 0)
factor = -factor;
if (factor > old_factor / 10)
printf("cc_calibrate_cpu[%u]: 10%% exceeded - delta %"
PRId64 ", denom %" PRId64 ", factor %" PRId64
", old factor %" PRId64"\n", ci->ci_index,
delta, denom, (delta * 1000) / denom, old_factor);
#endif /* TIMECOUNTER_DEBUG */
}